The present invention relates generally to inflatable restraint systems and, more particularly, to airbag cushions used in such systems.
It is well known to protect a vehicle occupant using a cushion or bag, e.g., an "airbag cushion," that is inflated or expanded with gas when the vehicle encounters sudden deceleration, such as in the event of a collision. In such systems, the airbag cushion is normally housed in an uninflated and folded condition to minimize space requirements. Upon actuation of the system, the cushion begins to be inflated, in a matter of no more than a few milliseconds, with gas produced or supplied by a device commonly referred to as "an inflator."
Such cushions typically take the form of one or more pieces of fabric sewn to define an interior chamber which receives the inflation gas. It is common that the interior chamber of the cushion be vented to permit controlled deflation of the cushion such as when it is compressed by contact with an occupant's body, and thereby serve to lessen the force of impact. While a simple fabric enclosure may be operable for an airbag cushion, forming an airbag cushion to include several compartments such as by the inclusion of internal partitions to essentially divide the cushion volume into several smaller cushion volumes can be done for various reasons including, for example, controlling inflation of the cushion such as by controlling the pressure differential between compartments during the inflation of the cushion or upon during engagement with the cushion by the occupant; controlling the shape of the cushion, such as during and upon deployment; and controlling deflation of the cushion.
The increased or greater use of compartmentalized airbag cushions has, however, been generally limited due to factors such as the normally greater costs and amounts of time associated with the construction and making of such airbag cushions.
As will be appreciated, the fabrication of compartmentalized airbag cushions typically requires additional stitching to form or create such cushion compartments. Further, such stitching is typically cumbersome and difficult to accomplish. For example, fabrication of a compartmentalized cushion often may require either or both that one or more of the airbag cushion panels or partially sewn airbag cushion compartments be inverted at one or more selected stages in the sewing process. In addition, the partial stitching of a cushion and inversion thereof to continue or complete stitching may not be possible with certain particular cushion designs. Alternatively or in addition, the fabrication of a compartmentalized cushion may typically involve the need to place a portion of a sewing machine or the like piece of fabrication equipment or a projection therefrom into the compartment being formed in order to complete the fabrication, e.g., sewing, associated therewith. It will further be appreciated that such stitching and fabrication steps generally additionally necessitate one or more various manual operations. At best, previous compartmentalized airbag cushion designs have typically required a great deal of folding, bending and other manual manipulations if internal compartments are to be to stitched formed therein. As a result, lower cost and typically more consistent automated manufacture of such airbag cushions may be effectively precluded. Further, such labor-intensive manual assembly can result in such a compartmentalized airbag cushion being cost prohibitive.